Narrative:

During flight, we experienced 'stabilizer trim' and 'mach trim' caution messages which could not be cleared per the QRH. This resulted in us declaring an emergency prior to landing at our destination of lga. It was day 3 of a 4 day trip. Leg 5 of 6 leg day with XA00 report. Earlier in the day we experienced problems (on 2 occasions) with the APU after which it was deferred by maintenance so we had no APU. Naturally, it was quite warm and we were all 'sweaty and uncomfortable' from the heat. Typical of summer operations with no APU. While we all were in bed early the night prior and slept about 7-8 hours each we were still tired from an event 2 nights prior in sav during which the hotel fire alarm sounded from XR22 until XU48 hours. We had an XX45 report and room searches by the fire department. This had nearly resulted in a 'fatigue call' however, we decided to press on with the trip. During climb out from pwm we received 'stabilizer trim' and 'mach trim' caution messages at 8000 ft MSL. I was flying and the first officer ran the QRH. Initially I thought that somehow I had knocked out both channels through the trim switch. Unusually high control forces (nose down) were required to control the aircraft. I reduced thrust to about 60-65% N1 which made the aircraft much more manageable. We completed the QRH and after several attempts the caution would not clear. Actually, each time it would initially clear and then resulted in 'autoplt trim' caution so I continued to hand fly. I told the first officer that we would be diverting to bos (as briefed during the takeoff briefing). Initially I was going to ask for vectors from 'center' while we worked the problem. However, I quickly decided that the aircraft was under good control in a slow steady climb. The frequency was quiet and there was little traffic in the area. It should be noted that this was my third time flying this same trip during the month. I figured we were 'out of the way' and could work through the problem better rather than getting into busy sector around bos. We had plenty of time and there were plenty of good airports available for diversions. Also bos was ideal in runways, proximity, maintenance availability and passenger accommodations, I told the first officer that while we would probably go to bos that we should call maintenance control for assistance and that we would continue on the flight plan. My first officer contacted maintenance who had us briefly troubleshoot the issue with no success. They informed us that there was no reason for us to divert, but that it was up to us and dispatch. There followed several mins of conversation between my first officer, dispatch and maintenance about our need to divert (during which time we obtained landing data from dispatch of runway length required of 3500 ft). During this conversation maintenance and dispatch both strongly disagreed with our decision to go to bos and wanted us to press on to lga. It seemed at first like a clear cut decision to me to divert. Even though now only an abnormal forward pressure was required on the yoke to control the aircraft and there was no immediate danger it seemed prudent to go to bos. I decided to xfer control of the aircraft to the first officer while I spoke with dispatch. This would also give the first officer a chance to fly the aircraft and allow him to generate his own thoughts on the aircraft handling for comparison. At this point I guess I had the mistake of presupposing that my decision would be supported by maintenance and thus dispatch, so I was quite surprised and a little irritated (irate) and I intended to strongly convey to dispatch my concerns about the aircraft and my desire to divert. So I was even more surprised when dispatch responded to me by emphatically stating that he did not agree with nor would he support my decision to go to bos. Callback conversation with reporter revealed the following information: reporter advised that this fleet has a history of this type of problem. It turned out that at landing confign (a reduced 20 degree flap setting is mandated by their QRH) control forces to maintain target approach speed were modest and a safe landing was completed well within the confines of the runway at lga. Reporter stated he was quite disillusioned by the lack of support by his maintenance and dispatch and distressed at himself for allowing his command decision making to be overwhelmed by his concerns regarding the possibility of company discipline for exercising the authority/authorized vested in him by the FARS. As a result of his as soon as possible report, considerable attention and review has been given to the incident. He was not, however, invited to represent his role in it. On the other side of the coin, he stressed that his chief pilot was very supportive and that his union safety people were actively involved in addressing his concerns with the company and the aircraft manufacturer representatives.

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Original NASA ASRS Text

Title: FLT CREW OF CL60 EXPERIENCE FAILURE OF STABILIZER TRIM AND MACH TRIM WHICH REQUIRED CONSTANT MANUAL ELEVATOR PRESSURE TO OVERCOME. WHEN THEY CONSIDERED A DEV THEY WERE NOT SUPPORTED BY COMPANY MAINT OR DISPATCH.

Narrative: DURING FLT, WE EXPERIENCED 'STABILIZER TRIM' AND 'MACH TRIM' CAUTION MESSAGES WHICH COULD NOT BE CLRED PER THE QRH. THIS RESULTED IN US DECLARING AN EMER PRIOR TO LNDG AT OUR DEST OF LGA. IT WAS DAY 3 OF A 4 DAY TRIP. LEG 5 OF 6 LEG DAY WITH XA00 RPT. EARLIER IN THE DAY WE EXPERIENCED PROBS (ON 2 OCCASIONS) WITH THE APU AFTER WHICH IT WAS DEFERRED BY MAINT SO WE HAD NO APU. NATURALLY, IT WAS QUITE WARM AND WE WERE ALL 'SWEATY AND UNCOMFORTABLE' FROM THE HEAT. TYPICAL OF SUMMER OPS WITH NO APU. WHILE WE ALL WERE IN BED EARLY THE NIGHT PRIOR AND SLEPT ABOUT 7-8 HRS EACH WE WERE STILL TIRED FROM AN EVENT 2 NIGHTS PRIOR IN SAV DURING WHICH THE HOTEL FIRE ALARM SOUNDED FROM XR22 UNTIL XU48 HRS. WE HAD AN XX45 RPT AND ROOM SEARCHES BY THE FIRE DEPT. THIS HAD NEARLY RESULTED IN A 'FATIGUE CALL' HOWEVER, WE DECIDED TO PRESS ON WITH THE TRIP. DURING CLBOUT FROM PWM WE RECEIVED 'STABILIZER TRIM' AND 'MACH TRIM' CAUTION MESSAGES AT 8000 FT MSL. I WAS FLYING AND THE FO RAN THE QRH. INITIALLY I THOUGHT THAT SOMEHOW I HAD KNOCKED OUT BOTH CHANNELS THROUGH THE TRIM SWITCH. UNUSUALLY HIGH CTL FORCES (NOSE DOWN) WERE REQUIRED TO CTL THE ACFT. I REDUCED THRUST TO ABOUT 60-65% N1 WHICH MADE THE ACFT MUCH MORE MANAGEABLE. WE COMPLETED THE QRH AND AFTER SEVERAL ATTEMPTS THE CAUTION WOULD NOT CLR. ACTUALLY, EACH TIME IT WOULD INITIALLY CLR AND THEN RESULTED IN 'AUTOPLT TRIM' CAUTION SO I CONTINUED TO HAND FLY. I TOLD THE FO THAT WE WOULD BE DIVERTING TO BOS (AS BRIEFED DURING THE TKOF BRIEFING). INITIALLY I WAS GOING TO ASK FOR VECTORS FROM 'CTR' WHILE WE WORKED THE PROB. HOWEVER, I QUICKLY DECIDED THAT THE ACFT WAS UNDER GOOD CTL IN A SLOW STEADY CLB. THE FREQ WAS QUIET AND THERE WAS LITTLE TFC IN THE AREA. IT SHOULD BE NOTED THAT THIS WAS MY THIRD TIME FLYING THIS SAME TRIP DURING THE MONTH. I FIGURED WE WERE 'OUT OF THE WAY' AND COULD WORK THROUGH THE PROB BETTER RATHER THAN GETTING INTO BUSY SECTOR AROUND BOS. WE HAD PLENTY OF TIME AND THERE WERE PLENTY OF GOOD ARPTS AVAILABLE FOR DIVERSIONS. ALSO BOS WAS IDEAL IN RWYS, PROX, MAINT AVAILABILITY AND PAX ACCOMMODATIONS, I TOLD THE FO THAT WHILE WE WOULD PROBABLY GO TO BOS THAT WE SHOULD CALL MAINT CTL FOR ASSISTANCE AND THAT WE WOULD CONTINUE ON THE FLT PLAN. MY FO CONTACTED MAINT WHO HAD US BRIEFLY TROUBLESHOOT THE ISSUE WITH NO SUCCESS. THEY INFORMED US THAT THERE WAS NO REASON FOR US TO DIVERT, BUT THAT IT WAS UP TO US AND DISPATCH. THERE FOLLOWED SEVERAL MINS OF CONVERSATION BTWN MY FO, DISPATCH AND MAINT ABOUT OUR NEED TO DIVERT (DURING WHICH TIME WE OBTAINED LNDG DATA FROM DISPATCH OF RWY LENGTH REQUIRED OF 3500 FT). DURING THIS CONVERSATION MAINT AND DISPATCH BOTH STRONGLY DISAGREED WITH OUR DECISION TO GO TO BOS AND WANTED US TO PRESS ON TO LGA. IT SEEMED AT FIRST LIKE A CLR CUT DECISION TO ME TO DIVERT. EVEN THOUGH NOW ONLY AN ABNORMAL FORWARD PRESSURE WAS REQUIRED ON THE YOKE TO CTL THE ACFT AND THERE WAS NO IMMEDIATE DANGER IT SEEMED PRUDENT TO GO TO BOS. I DECIDED TO XFER CTL OF THE ACFT TO THE FO WHILE I SPOKE WITH DISPATCH. THIS WOULD ALSO GIVE THE FO A CHANCE TO FLY THE ACFT AND ALLOW HIM TO GENERATE HIS OWN THOUGHTS ON THE ACFT HANDLING FOR COMPARISON. AT THIS POINT I GUESS I HAD THE MISTAKE OF PRESUPPOSING THAT MY DECISION WOULD BE SUPPORTED BY MAINT AND THUS DISPATCH, SO I WAS QUITE SURPRISED AND A LITTLE IRRITATED (IRATE) AND I INTENDED TO STRONGLY CONVEY TO DISPATCH MY CONCERNS ABOUT THE ACFT AND MY DESIRE TO DIVERT. SO I WAS EVEN MORE SURPRISED WHEN DISPATCH RESPONDED TO ME BY EMPHATICALLY STATING THAT HE DID NOT AGREE WITH NOR WOULD HE SUPPORT MY DECISION TO GO TO BOS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR ADVISED THAT THIS FLEET HAS A HISTORY OF THIS TYPE OF PROB. IT TURNED OUT THAT AT LNDG CONFIGN (A REDUCED 20 DEG FLAP SETTING IS MANDATED BY THEIR QRH) CTL FORCES TO MAINTAIN TARGET APCH SPD WERE MODEST AND A SAFE LNDG WAS COMPLETED WELL WITHIN THE CONFINES OF THE RWY AT LGA. RPTR STATED HE WAS QUITE DISILLUSIONED BY THE LACK OF SUPPORT BY HIS MAINT AND DISPATCH AND DISTRESSED AT HIMSELF FOR ALLOWING HIS COMMAND DECISION MAKING TO BE OVERWHELMED BY HIS CONCERNS REGARDING THE POSSIBILITY OF COMPANY DISCIPLINE FOR EXERCISING THE AUTH VESTED IN HIM BY THE FARS. AS A RESULT OF HIS ASAP RPT, CONSIDERABLE ATTN AND REVIEW HAS BEEN GIVEN TO THE INCIDENT. HE WAS NOT, HOWEVER, INVITED TO REPRESENT HIS ROLE IN IT. ON THE OTHER SIDE OF THE COIN, HE STRESSED THAT HIS CHIEF PLT WAS VERY SUPPORTIVE AND THAT HIS UNION SAFETY PEOPLE WERE ACTIVELY INVOLVED IN ADDRESSING HIS CONCERNS WITH THE COMPANY AND THE ACFT MANUFACTURER REPRESENTATIVES.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.